Casimir forces out of thermal equilibrium near a superconducting transition.

We present a comprehensive analysis of the out-of-equilibrium Casimir pressure between two high-[Formula: see text] superconducting plates, each kept at a different temperature. Two interaction regimes can be distinguished. While the zero-point energy dominates in the near field, thermal effects become important at large interplate separations causing a drop in the force's magnitude compared with the usual thermal-equilibrium case. Our detailed calculations highlight the competing role played by propagating and evanescent modes. Moreover, as one of the plates undergoes the superconducting transition, we predict an abrupt change in the force for any plate distance, which has not been previously observed in other systems. The sensitivity of the dielectric function of the high-[Formula: see text] superconductors makes them ideal systems for a possible direct measurement of the out-of-equilibrium Casimir pressure.

Near-field radiative heat transfer between high-temperature superconductors.

Near-field radiative heat transfer (NFRHT) management can be achieved using high-temperature superconductors. In this work, we present a theoretical study of the radiative heat transfer between two [Formula: see text] (YBCO) slabs in three different scenarios: Both slabs either in the normal or superconducting state, and only one of them below the superconductor critical temperature [Formula: see text]. The radiative heat transfer is calculated using Rytov's theory of fluctuating electrodynamics, while a two-fluid model describes the dielectric function of the superconducting materials. Our main result is the significant suppression of the NFRHT when one or both of the slabs are superconducting, which is explained in terms of the detailed balance of the charge carriers density together with the sudden reduction of the free electron scattering rate. A critical and unique feature affecting the radiative heat transfer between high-temperature superconductors is the large damping of the mid-infrared carriers which screens the surface plasmon excitation.

Modulated light absorption and emission of a luminescent layer by phase-controlled multiple beam illumination.

We propose a multiple beam illumination scheme to control the intensity of the light emitted by a thin luminescent layer. The experiment is designed to get as close as possible to the condition of Coherent Perfect Absorption (CPA) at a wavelength at which the absorption coefficient of the luminescent layer is low, and it is realized by externally acting on the phase difference between the incident beams. We elucidate experimental limitations that prevent the achievement of CPA in these slabs. Nevertheless, we are able to demonstrate that when the two beams destructively interfere outside the luminescent layer, the incident light is more efficiently absorbed by the luminescent layer and the intensity of the emitted light is phase-modulated.

Isolated left ventricular non compaction as possible cause of athletic training suspension: a preliminary study on screened athletes.

AIM: The aim of this paper was to determine the prevalence of isolated left ventricular noncomapction (ILVNC) in a sample of 150 athletes send by sports doctors to the Valmontone Hospital's Cardiology Division in a span of about three years, with particular interest in non-compacted segments evaluation. The prevention of cardiovascular complications occurring during sporting activity requires detection of pathologies most often clinically latent but whose first presentation can be sudden cardiac death. In Italy, the pre-participation screening program comprises family history and personal cardiac history, clinical examination and electrocardiography. Subjects with abnormalities are further investigated by stress test, echocardiography and laboratory investigations, and those with significant abnormalities are disqualified from sports training and competition. ILVNC results in multiple trabeculations in the left ventricular myocardium and it is postulated to be caused by intrauterine arrest of compaction of the myocardial fibres and meshwork, an important process in myocardial development. This cardiomyopathy should be considered one of the structural cardiac abnormalities responsible for sudden cardiac death. METHODS: There were 150 athletes seen in the Cardiology Division from 2007 to 2010 for an echocardiographic evaluation in order to clarify the nature of physical examination and/or electrocardiogram abnormalities. Echocardiographic diagnosis of ILVNC was based on criteria published by Jenni et al., and by Stölberger et al. RESULTS: Twenty-four of the 150 tested resulted positive for ILVNC (16.0%). This high prevalence is justified because it was a population originally selected because of electrocardiographic abnormalities. CONCLUSION: We believe that in case of unspecific ECG findings, it would be useful to perform echocardiographic examination in order to highlight structural defects. We also believe that it is very important to contemplate ILVNC between the causes of sudden death in young competitive athletes.

Hybrid plasmonic-photonic modes in diffractive arrays of nanoparticles coupled to light-emitting optical waveguides.

We study the hybridized plasmonic-photonic modes supported by two-dimensional arrays of metallic nanoparticles coupled to light-emitting optical waveguides. Localized surface plasmon polaritons in the metallic nanoparticles can couple to guided modes in the underlying waveguide, forming quasi-guided hybrid modes, or to diffracted orders in the plane of the array, forming surface lattice resonances. We consider three kinds of samples: one sustains quasi-guided modes only, another sustains surface lattice resonances only, and a third sample sustains both modes. This third sample constitutes the first demonstration of simultaneous coupling of localized surface plasmons to guided modes and diffracted orders. The dispersive properties of the modes in the samples are investigated through light extinction and emission spectroscopy. We elucidate the conditions that lead to the coexistence of surface lattice resonances and quasi-guided hybrid modes, and assess their potential for enhancing the luminescence of emitters embedded in the coupled waveguide. We find the largest increase in emission intensity for the surface lattice resonances, reaching up to a factor of 20.

Excitation of confined modes on particle arrays.

We describe both theoretically and experimentally the existence and excitation of confined modes in planar arrays of gold nanodisks. Ordered 2D lattices of monodispersive nanoparticles are manufactured, embedded in a silica matrix, and exposed to evanescent prism-coupling illumination, leading to dark features in the reflectivity, which signal the presence of confined modes guided along the arrays. We find remarkable agreement between theory and experiment in the frequency-momentum dispersion of the resonances. Direct excitation of these modes reveals long propagation distances and deep extinction features. This combined experimental and theoretical characterization of guided modes shows a good understanding of the optical response of metallic particles arrays, which can be beneficial in future designs of optical-signal and distant-sensing applications.